/*
GanttProject is an opensource project management tool.
Copyright (C) 2005-2011 GanttProject Team

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
*/
package net.sourceforge.ganttproject.action.scroll;

import java.awt.event.ActionEvent;
import java.util.Collections;
import java.util.Date;
import java.util.List;

import net.sourceforge.ganttproject.action.GPAction;
import net.sourceforge.ganttproject.chart.TimelineChart;
import net.sourceforge.ganttproject.gui.UIFacade;
import net.sourceforge.ganttproject.task.Task;
import net.sourceforge.ganttproject.task.TaskSelectionManager;

public class ScrollToSelectionAction extends GPAction implements TaskSelectionManager.Listener {
    private final TimelineChart myChart;
    private List<Task> mySelectedTasks;
    
    public ScrollToSelectionAction(UIFacade uiFacade, TimelineChart chart) {
        super("scroll.selection");
        myChart = chart;
        mySelectedTasks = Collections.emptyList();
        uiFacade.getTaskSelectionManager().addSelectionListener(this);
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        if (mySelectedTasks.isEmpty()) {
            return;
        }
        Date earliestStartDate = null;
        for (Task selectedTask : mySelectedTasks) {
            if (earliestStartDate == null || earliestStartDate.after(selectedTask.getStart().getTime())) {
                earliestStartDate = selectedTask.getStart().getTime();
            }
        }
        myChart.setStartDate(earliestStartDate);
    }

    @Override
    public void selectionChanged(List<Task> currentSelection) {
        mySelectedTasks = currentSelection;
        setEnabled(!currentSelection.isEmpty());
    }

    @Override
    public void userInputConsumerChanged(Object newConsumer) {
    }
}